LXR linux/arch/x86/lib/putuser.S

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * __put_user functions.
   4 *
   5 * (C) Copyright 2005 Linus Torvalds
   6 * (C) Copyright 2005 Andi Kleen
   7 * (C) Copyright 2008 Glauber Costa
   8 *
   9 * These functions have a non-standard call interface
  10 * to make them more efficient, especially as they
  11 * return an error value in addition to the "real"
  12 * return value.
  13 */
  14#include <linux/linkage.h>
  15#include <asm/thread_info.h>
  16#include <asm/errno.h>
  17#include <asm/asm.h>
  18#include <asm/smap.h>
  19#include <asm/export.h>
  20
  21
  22/*
  23 * __put_user_X
  24 *
  25 * Inputs:      %eax[:%edx] contains the data
  26 *              %ecx contains the address
  27 *
  28 * Outputs:     %eax is error code (0 or -EFAULT)
  29 *
  30 * These functions should not modify any other registers,
  31 * as they get called from within inline assembly.
  32 */
  33
  34#define ENTER   mov PER_CPU_VAR(current_task), %_ASM_BX
  35#define EXIT    ASM_CLAC ;      \
  36                ret
  37
  38.text
  39ENTRY(__put_user_1)
  40        ENTER
  41        cmp TASK_addr_limit(%_ASM_BX),%_ASM_CX
  42        jae bad_put_user
  43        ASM_STAC
  441:      movb %al,(%_ASM_CX)
  45        xor %eax,%eax
  46        EXIT
  47ENDPROC(__put_user_1)
  48EXPORT_SYMBOL(__put_user_1)
  49
  50ENTRY(__put_user_2)
  51        ENTER
  52        mov TASK_addr_limit(%_ASM_BX),%_ASM_BX
  53        sub $1,%_ASM_BX
  54        cmp %_ASM_BX,%_ASM_CX
  55        jae bad_put_user
  56        ASM_STAC
  572:      movw %ax,(%_ASM_CX)
  58        xor %eax,%eax
  59        EXIT
  60ENDPROC(__put_user_2)
  61EXPORT_SYMBOL(__put_user_2)
  62
  63ENTRY(__put_user_4)
  64        ENTER
  65        mov TASK_addr_limit(%_ASM_BX),%_ASM_BX
  66        sub $3,%_ASM_BX
  67        cmp %_ASM_BX,%_ASM_CX
  68        jae bad_put_user
  69        ASM_STAC
  703:      movl %eax,(%_ASM_CX)
  71        xor %eax,%eax
  72        EXIT
  73ENDPROC(__put_user_4)
  74EXPORT_SYMBOL(__put_user_4)
  75
  76ENTRY(__put_user_8)
  77        ENTER
  78        mov TASK_addr_limit(%_ASM_BX),%_ASM_BX
  79        sub $7,%_ASM_BX
  80        cmp %_ASM_BX,%_ASM_CX
  81        jae bad_put_user
  82        ASM_STAC
  834:      mov %_ASM_AX,(%_ASM_CX)
  84#ifdef CONFIG_X86_32
  855:      movl %edx,4(%_ASM_CX)
  86#endif
  87        xor %eax,%eax
  88        EXIT
  89ENDPROC(__put_user_8)
  90EXPORT_SYMBOL(__put_user_8)
  91
  92bad_put_user:
  93        movl $-EFAULT,%eax
  94        EXIT
  95END(bad_put_user)
  96
  97        _ASM_EXTABLE(1b,bad_put_user)
  98        _ASM_EXTABLE(2b,bad_put_user)
  99        _ASM_EXTABLE(3b,bad_put_user)
 100        _ASM_EXTABLE(4b,bad_put_user)
 101#ifdef CONFIG_X86_32
 102        _ASM_EXTABLE(5b,bad_put_user)
 103#endif
 104